E-Beam Enhanced Decoupled Source for Semiconductor Processing

ABSTRACT

A semiconductor substrate processing system includes a processing chamber and a substrate support defined to support a substrate in the processing chamber. The system also includes a plasma chamber defined separate from the processing chamber. The plasma chamber is defined to generate a plasma. The system also includes a plurality of fluid transmission pathways fluidly connecting the plasma chamber to the processing chamber. The plurality of fluid transmission pathways are defined to supply reactive constituents of the plasma from the plasma chamber to the processing chamber. The system further includes an electron injection device for injecting electrons into the processing chamber to control an electron energy distribution within the processing chamber so as to in turn control an ion-to-radical density ratio within the processing chamber. In one embodiment, an electron beam source is defined to transmit an electron beam through the processing chamber above and across the substrate support.

CLAIM OF PRIORITY

This application claims priority under 35 U.S.C. 119(e) to U.S.Provisional Patent Application No. 61/555,639, filed Nov. 4, 2011,entitled “E-Beam Enhanced Decoupled Source for SemiconductorProcessing,” the disclosure of which is incorporated herein by referencein its entirety. This application is also a continuation-in-partapplication under 35 U.S.C. 120 of prior U.S. Application No.13/084,325, filed Apr. 11, 2011, and entitled “Multi-Frequency HollowCathode and Systems Implementing the Same.” This application is also acontinuation-in-part application under 35 U.S.C. 120 of prior U.S.Application No. 13/104,923, filed May 10, 2011, and entitled“Semiconductor Processing System Having Multiple Decoupled PlasmaSources.” The above-identified patent applications are incorporatedherein by reference in their entirety.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is related to U.S. patent application Ser. No. ______(Attorney Docket No.: LAM2P709B), filed on an even date herewith, andentitled “E-Beam Enhanced Decoupled Source for SemiconductorProcessing,” which is incorporated herein by reference in its entirety.This application is also related to U.S. patent application Ser. No.______ (Attorney Docket No.: LAM2P709C), filed on an even date herewith,and entitled “E-Beam Enhanced Decoupled Source for SemiconductorProcessing,” which is incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

Plasma sources utilized for thin film processing in semiconductor devicefabrication are often unable to achieve the most desirable condition fordry etching due to the inability to separately control ion and radicalconcentrations in the plasma. For example, in some applications, thedesirable conditions for plasma etching would be achieved by increasingthe ion concentration in the plasma while simultaneously maintaining theradical concentration at a constant level. However, this type ofindependent ion concentration versus radical concentration controlcannot be achieved using the common plasma source typically used forthin film processing. It is within this context that the presentinvention arises.

SUMMARY OF THE INVENTION

In one embodiment, a semiconductor substrate processing system isdisclosed. The system includes a processing chamber and a substratesupport defined to support a substrate in the processing chamber. Thesystem also includes a plasma chamber defined separate from theprocessing chamber. The plasma chamber is defined to generate a plasma.The system also includes a plurality of fluid transmission pathwaysfluidly connecting the plasma chamber to the processing chamber. Theplurality of fluid transmission pathways are defined to supply reactiveconstituents of the plasma from the plasma chamber to the processingchamber. The system further includes an electron beam source defined togenerate an electron beam and transmit the electron beam through theprocessing chamber above and across the substrate support.

In one embodiment, a method is disclosed for processing a semiconductorsubstrate. The method includes an operation for placing a substrate on asubstrate support in exposure to a processing region. The method alsoincludes an operation for generating a plasma in a plasma generationregion separate from the processing region. The method also includes anoperation for supplying reactive constituents of the plasma from theplasma generation region to the processing region. The method furtherincludes an operation for injecting electrons into the processing regionover the substrate, whereby the injected electrons modify an ion densityin the processing region to affect processing of the substrate.

Other aspects and advantages of the invention will become more apparentfrom the following detailed description, taken in conjunction with theaccompanying drawings, illustrating by way of example the presentinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a simplified schematic of a semiconductor substrateprocessing system that utilizes a plasma chamber defined separate from asubstrate processing chamber, in accordance with one embodiment of thepresent invention.

FIG. 2 shows a plot of ion density in the ion source region needed toobtain a 1.0E11 cc⁻¹ ion density in the substrate processing chamber asa function of tube hole diameter, where the tubes represent theconveyance means between the ion source region and the substrateprocessing chamber, in accordance with one embodiment of the presentinvention.

FIG. 3A shows a vertical cross-section of a plasma-driven substrateprocessing system, in accordance with one embodiment of the presentinvention.

FIG. 3B shows a horizontal cross-section view A-A as referenced in FIG.3A, in accordance with one embodiment of the present invention.

FIG. 3C shows a variation of the horizontal cross-section view of FIG.3B in which the spacing between the fluid transmission pathways acrossthe top plate is decreased, in accordance with one embodiment of thepresent invention.

FIG. 3D shows a variation of the horizontal cross-section view of FIG.3B in which the spacing between the fluid transmission pathways acrossthe top plate is increased, in accordance with one embodiment of thepresent invention.

FIG. 3E shows a variation of the horizontal cross-section view of FIG.3B in which the spacing between the fluid transmission pathways acrossthe top plate is non-uniform, in accordance with one embodiment of thepresent invention.

FIG. 3F shows a top view of the substrate support in a systemconfiguration in which an electron beam source is defined to transmitultiple spatially separated electron beams through the substrateprocessing region, above and across the substrate support, in a commondirection, in accordance with one embodiment of the present invention.

FIG. 3G shows a top view of the substrate support in the systemconfiguration in which multiple electron beam sources are defined totransmit ultiple spatially separated electron beams through thesubstrate processing region, above and across the substrate support, inrespective multiple directions, in accordance with one embodiment of thepresent invention.

FIG. 3H shows a rasterized temporal sequence for operation of themultiple electron beam sources of FIG. 3G, in accordance with oneembodiment of the present invention.

FIG. 4A shows an example electron beam source defined as a hollowcathode device, in accordance with one embodiment of the presentinvention.

FIG. 4B shows a front view of the conductive grid, in accordance withone embodiment of the present invention.

FIG. 5A shows a variation of the plasma-driven substrate processingsystem that implements a DC-biased surface electron beam source, inaccordance with one embodiment of the present invention.

FIG. 5B shows a close-up view of the electrode, in accordance with oneembodiment of the present invention.

FIG. 6A shows a variation of the plasma-driven substrate processingsystem that implements a planar DC-biased surface electron beam source,in accordance with one embodiment of the present invention.

FIG. 6B shows a close-up view of the planar electrode, in accordancewith one embodiment of the present invention.

FIG. 7 shows a variation of the plasma-driven substrate processingsystem that utilizes the fluid transmission pathways as supplementaryion generation regions, in accordance with one embodiment of the presentinvention.

FIG. 8 shows a flowchart of a method for processing a semiconductorsubstrate, in accordance with one embodiment of the present invention.

FIG. 9 shows a flowchart of a method for processing a semiconductorsubstrate, in accordance with one embodiment of the present invention.

FIG. 10 shows a flowchart of a method for processing a semiconductorsubstrate, in accordance with one embodiment of the present invention.

DETAILED DESCRIPTION

In the following description, numerous specific details are set forth inorder to provide a thorough understanding of the present invention. Itwill be apparent, however, to one skilled in the art that the presentinvention may be practiced without some or all of these specificdetails. In other instances, well known process operations have not beendescribed in detail in order not to unnecessarily obscure the presentinvention.

Plasma sources utilized for thin film semiconductor processing are oftenunable to achieve the most desirable condition for dry etching due tothe inability to separately adjust ion and radical concentrations in theplasma. In many applications, the desirable conditions for plasmaetching would be achieved by increasing the ion concentrations, while atthe same time maintaining the radical concentration at a substantiallyconstant level. However, it is difficult at best to achieve this type ofadjustment through conventional plasma sources that are used for thinfilm processing.

The concept of providing separate control of ion concentration andradical concentration in a semiconductor processing plasma is referredto herein as providing a decoupled ion/radical plasma source. Oneconcept for providing the decoupled ion/radical plasma source is toinject radicals and ions from separate plasma sources. In variousembodiments, these separate plasma sources can be either spatiallyseparated or temporally separated, i.e., defined to generate primarilyion or primarily radicals at different times. Examples of decoupledion/radical plasma sources that utilize spatial separation, temporalseparation, or a combination thereof are described in co-pending U.S.patent application Ser. No. 13/104,923, filed on May 10, 2011, entitled“Semiconductor Processing System Having Multiple Decoupled PlasmaSources.”

A plasma-driven substrate processing system that relies upon radicalspecies of a plasma to provide some processing of the semiconductorsubstrate may generate the plasma in a plasma chamber separate from thesubstrate processing chamber due to differences between theenvironmental requirements, i.e., pressure, temperature, gascomposition, gas flow rate, power supply, of the plasma chamber and thesubstrate processing chamber. FIG. 1 shows a simplified schematic of asemiconductor substrate processing system 100 that utilizes a plasmachamber 101 defined separate from a substrate processing chamber 103, inaccordance with one embodiment of the present invention. In the system100, the plasma generation chamber 101 is fluidly connected to thesubstrate processing chamber 103 by a number of fluid transmissionpathways 105. In this manner, the reactive species of the plasmagenerated within the plasma generation chamber 101 travel through thefluid transmission pathways 105 into the substrate processing chamber103, as indicated by arrows 107. In one embodiment, some of the fluidtransmission pathways 105 are defined to include an energizable regiondefined to provide supplemental electron generation to increase ionextraction from the plasma generation chamber 355. Upon entering thesubstrate processing chamber 103, the reactive species of the plasmainteract with a substrate 109 so as to process the substrate 109 in aprescribed manner.

In one embodiment, the term “substrate” as used herein refers to asemiconductor wafer. However, it should be understood that in otherembodiments, the term “substrate” as used herein can refer to substratesformed of sapphire, GaN, GaAs or SiC, or other substrate materials, andcan include glass panels/substrates, metal foils, metal sheets, polymermaterials, or the like. Also, in various embodiments, the “substrate” asreferred to herein may vary in form, shape, and/or size. For example, insome embodiments, the “substrate” as referred to herein may correspondto a 200 mm (millimeters) semiconductor wafer, a 300 mm semiconductorwafer, or a 450 mm semiconductor wafer. Also, in some embodiments, the“substrate” as referred to herein may correspond to a non-circularsubstrate, such as a rectangular substrate for a flat panel display, orthe like, among other shapes. The “substrate” referred to herein isdenoted in the various example embodiment figures as substrate 109.

In most plasma processing applications, it is desirable to utilize bothion species and radical species of the plasma to process the substrate109. Because radical species are electrically neutral, the radicalspecies can travel from the plasma generation chamber 101 through thefluid transmission pathways 105 to the substrate processing chamber 103in conjunction with a flow of process gas. However, because ion speciesare electrically charged and can be electrically neutralized uponcontact with a material surface, it can be difficult to achieve acontrolled and efficient transfer of ions from the plasma generationchamber 101 through the fluid transmission pathways 105 to the substrateprocessing chamber 103.

It should be appreciated that injection of ions from a remote source toa substrate processing region can be problematic. As mentioned above, ifthe ion source is spatially separate from the substrate processingregion, the ions must be transported through a conveyance means betweenthe ion source and the substrate processing region. In differentembodiments, the conveyance means can be defined in many different ways.For example, in one embodiment, the ion source is generated in a chamberphysically separate from the substrate processing chamber and theconveyance means is defined by an array of tubes. In another embodiment,a chamber for generating the ion source is separated from the substrateprocessing chamber by a plate assembly, and the conveyance means isdefined by a number of through-holes formed through the plate assembly.It should be understood that the above-mentioned examples of theconveyance means are provided by way example only. In other embodiments,the conveyance means can be defined in other ways, so long as theconveyance means provides one or more fluid transmission pathwaysbetween a region in which the ion/radical source, i.e., plasma, isgenerated and the substrate processing region.

At best, an ion flux achievable in a secondary substrate processingchamber is a product of an ion density in an ion source region and theBohm velocity, where the Bohm velocity represents the speed of ions atan edge of a surface sheath in the ion source region. The surface sheathrepresents a region in front of a material surface that is in contactwith the ion source plasma and that is in the presence of an electricfield. The total number of ions available to the substrate processingchamber per unit time is then the product of the ion flux in the ionsource region, i.e., in the plasma generation chamber, multiplied by atotal flow area of the conveyance means (fluid transmission pathways)between the ion source region and the substrate processing chamber.

A balance equation exists in which an extra ion flux to the walls in theplasma processing chamber due to ions injected from the ion sourceregion is equal to the ion flux injected from the ion source regionthrough the conveyance means, as follows:

$\begin{matrix}{n_{upper} = {\frac{\Delta \; n}{\left( \frac{v_{bohm\_ upper}A_{open}}{v_{bohm\_ lower}A_{loss\_ lower}} \right)}.}} & {{Equation}\mspace{14mu} 1}\end{matrix}$

where n_(upper)=number density of ions in ion source region, Δn=additionto number density of ions in substrate processing chamber from ionsource region, v_(bohm) _(—) _(upper)=Bohm velocity of ions in ionsource region, A_(open)=total area of conveyance means between ionsource region and substrate processing chamber, A_(loss) _(—)_(lower)=total area of walls of substrate processing chamber, andV_(bohm) _(—) _(lower)=Bohm velocity of ions in substrate processingchamber.

The Bohm velocity is given by Equation 2.

$\begin{matrix}{v_{bohm} = {\left( \frac{9.8\; E\; 5\mspace{14mu} T_{e}}{m_{i}} \right)^{1\text{/}2}\mspace{14mu} {cm}\text{/}{\sec.}}} & {{Equation}\mspace{14mu} 2}\end{matrix}$

where v_(bohm)=Bohm velocity of ion, T_(e)=temperature of ion (eV), andm_(i)=mass of ion (amu).

According to Equation 1, maximizing the ion density in the substrateprocessing chamber can be accomplished by one or more of thefollowing: 1) increasing the number density of ions in the ion sourceregion, i.e., increasing n_(upper), 2) increasing the electrontemperature in the ion source, i.e., increasing V_(bohm) _(—) _(upper),and 3) minimizing ion losses in the conveyance means between the ionsource and the substrate processing chamber.

A total flow area of the conveyance means between the ion source regionand the substrate processing chamber can be quite small. For example,small tube diameters or a small numbers of holes of small diameter maybe needed to maintain an adequate pressure differential between thehigher pressure ion source region and the lower pressure substrateprocessing chamber. Therefore, because large gas densities, i.e., highgas pressures, may be needed in the ion source region to achieve asufficient amount of electron production, it may not be feasible tosimply increase the flow area of the conveyance means between the ionsource region and the substrate processing chamber.

Additionally, it can be difficult to increase the ion number density andelectron temperature in the ion source region to the degree needed tocompensate for the small flow area of the conveyance means between theion source region and the substrate processing chamber. FIG. 2 shows aplot of ion density in the ion source region needed to obtain a 1.0E11cc⁻¹ ion density in the substrate processing chamber as a function oftube hole diameter, where the tubes represent the conveyance meansbetween the ion source region and the substrate processing chamber, inaccordance with one embodiment of the present invention. As shown inFIG. 2, if ion densities of 1.0E11 cc⁻¹ were needed above the substratein the substrate processing chamber, t may be necessary to have an iondensity in the ion source region on the order of 1.0E12 cc⁻¹. Achievingan ion density level on the order of 1.0E11 cc⁻¹ in the substrateprocessing chamber with a tube conveyance means having a diameter lessthan 2 mm (millimeters) may be possible in very specialized and oftenimpractical circumstances.

An additional issue for separately controlling ion flux and radical fluxin the substrate processing chamber is generating an ion flux in thepresence of low electron temperature, particularly when the substrateprocessing chamber is operated at low pressure. For example, it may bedifficult to generate an ion flux in a process that requires minimum“damage” to the substrate by maintaining an ultra low electrontemperature in exposure to the substrate, such as in an atomic layeretching (ALE) process, which is an atomic layer deposition process thatforms epitaxial layer on the substrate. By way of example, consider anALE process in which a thin film was deposited at low electrontemperature, followed by a processing step to remove a monolayer ofmaterial which requires higher electron temperature. In this example, itmay be difficult to adjust the ion flux to accomplish the monolayerremoval process step given the low electron temperature of the precedingALE process step.

It should be understood that having an ability to control the electronenergy distribution function (EEDF) in the substrate processing chamberis itself a means of providing separate (decoupled) control of iondensity relative to radical density within the substrate processingchamber. More specifically, having an ability to control the EEDF to“select” families of electrons that avoid low energy dissociationprocesses, and favor higher energy ionization or dissociative ionizationprocesses, can increase the ion flux relative to the radical flux withinthe substrate processing chamber, or can increase the ion flux relativeto the flux of unbeneficial radicals within the substrate processingchamber.

Several plasma-driven substrate processing system embodiments aredisclosed herein to provide for adequate and large ion flux in plasmasources that exploit multiplexed ion and radical sources for ion andradical control. The plasma-driven substrate processing systemembodiments disclosed herein also provide for achieving large ion fluxwith non-damaging ion and electron energies in applications that mayrequire such large ion flux, such as ALE.

Electron beam injection into the substrate processing chamber acts tolower the “bulk” electron temperature and plasma potential throughcharge addition. Therefore, the EEDF within the substrate processingchamber can be modified through electron beam injection. Morespecifically, electron beam injection into the substrate processingregion has the effect of dropping the rate of low energy electron impactprocesses, e.g., dissociative electron impact processes. At electronenergies above about 100 eV (electronvolts), electron interactionprocesses that include charged particle production have much largercross-sections than electron interaction processes without chargedparticle production. Therefore, the family of high-energy electrons orbeam-injected electrons can sustain the plasma discharge throughhigh-energy electron interaction processes. The plasma-driven substrateprocessing system embodiments disclosed herein implement various typesof electron injection technology to maximize the ion flux available to asubstrate and to provide for decoupling of ion and radical flux controlwithin the substrate processing chamber.

FIG. 3A shows a vertical cross-section of a plasma-driven substrateprocessing system 300, in accordance with one embodiment of the presentinvention. The system 300 includes a chamber 301 formed by a topstructure 301B, a bottom structure 301C, and sidewalls 301A extendingbetween the top structure 301B and bottom structure 301C. The chamber301 encloses a substrate processing region 302 in which the substrate109 is held in a secured manner on a substrate support 303 and isexposed to reactive constituents 325 of a plasma 359. The substrateprocessing region 302 is separated from a plasma generation chamber 355by a top plate 315. During operation, the reactive constituents 325 ofthe plasma 359 travel through a number of fluid transmission pathways316 within the top plate 315 to reach the substrate processing region302, as indicated by arrows 361.

In various embodiments, the chamber sidewalls 301A, top structure 301B,and bottom structure 301C can be formed from different materials, suchas stainless steel or aluminum, by way of example, so long as thechamber 301 materials are structurally capable of withstanding pressuredifferentials and temperatures to which they will be exposed duringplasma processing, and are chemically compatible with the plasmaprocessing environment. Also, in one embodiment, the chamber sidewalls301A, top structure 301B, and bottom structure 301C are formed of anelectrically conductive material, and are electrically connected to anelectrical ground 357.

In the embodiment of FIG. 3A, the plasma generation chamber 355 isformed above the top plate 315. The plasma generation chamber 355 is influid communication with both a process gas source 319 and each of thefluid transmission pathways 316 through the top plate 315. The system300 also includes a coil assembly 351 disposed to transform the processgas within the plasma generation chamber 355 into the plasma 359. In thesystem 300, the chamber top plate 301B includes a window 353 that issuitable for transmission of RF (radiofrequency) power from the coilassembly 351 into the plasma generation chamber 355. In one embodiment,the window 353 is formed from quartz. In another embodiment, the window353 is formed from a ceramic material, such as silicon carbide.

In one embodiment, RF power is delivered to the coil assembly 351 fromone or more RF power sources 391A-391 n. Each RF power source 391A-391 nis connected through respective matching circuitry 393 to ensureefficient RF power transmission to the coil assembly 351. In the case ofmultiple RF power sources 391A-391 n, it should be understood that eachof the multiple RF power sources 391A-391 n can be independentlycontrolled with regard to RF power frequency and/or amplitude. In oneembodiment, the one or more RF power source 391A-391 n are defined tosupply RF power having a frequency of either 2 MHz, 27 MHz, 60 MHz, 400kHz, or a combination thereof.

It should be understood that the inductive power delivery system of FIG.3A is shown by way of example. In other embodiments, the plasmageneration chamber 355 can be defined to generate the plasma 359 indifferent ways. For example, in one embodiment, the plasma generationchamber 355 can be defined as a capacitively coupled chamber, in whichthe plasma 359 generation region of the chamber 355 is exposed to a pairof spaced apart electrodes that are electrically connected to one ormore power supplies, such that power (either direct current (DC), RF, ora combination thereof) is transmitted between the pair of electrodes andthrough the chamber 355, so as to transform the process gas deliveredfrom the process gas source 319 into the plasma 359. In yet anotherembodiment, the plasma generation chamber 355 can be defined as amicrowave-driven chamber.

Regardless of the particular power delivery embodiment for generation ofthe plasma 359, it should be understood that during operation of thesystem 300, process gases supplied by the process gas source 319 aretransformed into the plasma 359 within the plasma generation chamber355. As a result, reactive constituents 325 of the plasma 359 move fromthe plasma generation chamber 355, through the number fluid transmissionpathways 316 of the top plate 315, to the substrate processing region302 over the substrate support 303, and onto the substrate 109 whendisposed on the substrate support 303.

In one embodiment, upon entering the substrate processing region 302from the fluid transmission pathways 316 of the top plate 315, theprocess gases flow through peripheral vents 327, and are pumped outthrough exhaust ports 329 by an exhaust pump 331, as indicated by arrows381. In one embodiment, a flow throttling device 333 is provided tocontrol a flow rate of the process gases from the substrate processingregion 302. Also, in one embodiment, the flow throttling device 333 isdefined as a ring structure that is movable toward and away from theperipheral vents 327, as indicated by arrows 335.

In one embodiment, the plasma generation chamber 355 is defined tooperate at internal pressure up to about one Ton (T). Also, in oneembodiment, the substrate processing region 302 is operated within apressure range extending from about 1 milliTorr (mT) to about 100 mT.For example, in one embodiment, the system 300 is operated to provide asubstrate processing region 302 pressure of about 10 mT, with a processgas throughput flow rate of about 1000 scc/sec (standard cubiccentimeters per second), and with a residence time of the reactiveconstituents 325 within the substrate processing region 302 of about 10milliseconds (ms). It should be understood and appreciated that theabove example operating conditions represent one of an essentiallylimitless number of operating conditions that can be achieved with thesystem 300. The above example operating conditions do not represent orimply any limitation on the possible operating conditions of the system300.

The substrate support 303 is disposed to support the substrate 109 inexposure to the substrate processing region 302. The substrate support303 is defined to hold the substrate 109 thereon during performance ofplasma processing operations on the substrate 109. In the exampleembodiment of FIG. 3A, the substrate support 303 is held by acantilevered arm 305 affixed to a wall 301A of the chamber 301. However,in other embodiments, the substrate support 303 can be affixed to thebottom plate 301C of the chamber 301 or to another member disposedwithin the chamber 301. In various embodiments, the substrate support303 can be formed from different materials, such as stainless steel,aluminum, or ceramic, by way of example, so long as the substratesupport 303 material is structurally capable of withstanding pressuredifferentials and temperatures to which it will be exposed during plasmaprocessing, and is chemically compatible with the plasma processingenvironment.

In one embodiment, the substrate support 303 includes a bias electrode307 for generating an electric field to attract ions toward thesubstrate support 303, and thereby toward the substrate 109 held on thesubstrate support 303. More specifically, the electrode 307 within thesubstrate support 303 is defined to apply a bias voltage across thesubstrate processing region 302 between the substrate support 303 andthe top plate 315. The bias voltage generated by the electrode 307serves to pull ions that are formed within the plasma generation chamber355 through the fluid transmission pathways 316 into the substrateprocessing region 302 and toward the substrate 109.

In one embodiment, the substrate support 303 includes a number ofcooling channels 309 through which a cooling fluid can be flowed duringplasma processing operations to maintain temperature control of thesubstrate 109. Also, in one embodiment, the substrate support 303 caninclude a number of lifting pins 311 defined to lift and lower thesubstrate 109 relative to the substrate support 303. In one embodiment,a door assembly 313 is disposed within the chamber wall 301A to enableinsertion and removal of the substrate 109 into/from the chamber 301.Additionally, in one embodiment, the substrate support 303 is defined asan electrostatic chuck equipped to generate an electrostatic field forholding the substrate 109 securely on the substrate support 303 duringplasma processing operations.

The top plate 315 is disposed within the chamber 301 above and spacedapart from the substrate support 303, so as to be positioned above andspaced apart from the substrate 109 when positioned on the substratesupport 303. The substrate processing region 302 exists between the topplate 315 and the substrate support 303, so as to exist over thesubstrate 109 when positioned on the substrate support 303.

In one embodiment, the substrate support 303 is movable in a verticaldirection, as indicated by arrows 383, such that a process gap distanceas measured perpendicularly across the substrate processing region 302between the top plate 315 and substrate support 303 is adjustable withina range extending from about 1 cm to about 10 cm. In one embodiment, thesubstrate support 303 is adjusted to provide a process gap distance ofabout 5 cm. Also, in one embodiment, a vertical position of thesubstrate support 303 relative to the top plate 315, vice-versa, isadjustable either during performance of a plasma processing operation orbetween plasma processing operations.

Adjustment of the process gap distance provides for adjustment of adynamic range of the ion flux emanating from the fluid transmissionpathways 316. Specifically, the ion flux that reaches the substrate 109can be decreased by increasing the process gap distance, vice versa. Inone embodiment, when the process gap distance is adjusted to achieve anadjustment in the ion flux at the substrate 109, the process gas flowrate through the plasma generation chamber 355 can be correspondinglyadjusted, thereby providing a level of independence in the control ofradical flux at the substrate 109. Additionally, it should beappreciated that the process gap distance in combination with the ionand radical fluxes emanating from the fluid transmission pathways 316into the substrate processing region 302 are controlled to provide for asubstantially uniform ion density and radical density at and across thesubstrate 109.

It should be appreciated that the configuration of fluid transmissionpathways 316 through the top plate 315 can influence how the reactiveconstituents 325 of the plasma 359 are distributed within the substrateprocessing region 302. In one embodiment, the fluid transmissionpathways 316 are formed through the top plate 315 in a substantiallyuniformly distributed manner relative to the underlying substratesupport 303. FIG. 3B shows a horizontal cross-section view A-A asreferenced in FIG. 3A, in accordance with one embodiment of the presentinvention. As shown in FIG. 3B, the fluid transmission pathways 316 areformed through the top plate 315 in a substantially uniformlydistributed manner relative to the underlying substrate support 303.

It should be appreciated that the spacing between the fluid transmissionpathways 316 across the top plate 315 can be varied among differentembodiments. FIG. 3C shows a variation of the horizontal cross-sectionview of FIG. 3B in which the spacing between the fluid transmissionpathways 316 across the top plate 315 is decreased, in accordance withone embodiment of the present invention. FIG. 3D shows a variation ofthe horizontal cross-section view of FIG. 3B in which the spacingbetween the fluid transmission pathways 316 across the top plate 315 isincreased, in accordance with one embodiment of the present invention.FIG. 3E shows a variation of the horizontal cross-section view of FIG.3B in which the spacing between the fluid transmission pathways 316across the top plate 315 is non-uniform, in accordance with oneembodiment of the present invention.

In one example embodiment, a total number of the fluid transmissionpathways 316 through the top plate 315 is within a range extending fromabout 50 to about 200. In one example embodiment, a total number of thefluid transmission pathways 316 through the top plate 315 is about 100.It should be understood, however, that the above-mentioned exampleembodiments for the number and configuration of the fluid transmissionpathways 316 through the top plate 315 are provided by way of example tofacilitate description of the present invention. In other embodiments,essentially any number and configuration of fluid transmission pathways316 can be defined and arranged through the top plate 315 as necessaryto provide an appropriate mixture and distribution of reactiveconstituents 325, i.e., radicals and/or ions, within the substrateprocessing region 302, so as to achieve a desired plasma processingresult on the substrate 109.

The plasma-driven substrate processing system 300 of FIG. 3A furtherincludes at least one electron beam source 363 defined to generate anelectron beam 367 and transmit the electron beam 367 through thesubstrate processing region 302 above and across the substrate support303. Each electron beam source 363 is electrically connected to receivepower from a power supply 389, such that power can be supplied to eachelectron beam source 363 in an independently controlled manner.Depending on the type of electron beam source 363, the power supply 389can be defined to transmit DC power, RF power, or a combination thereof,to the electron beam sources 363.

In one embodiment, each electron beam source 363 is defined to transmitthe electron beam 367 along a trajectory substantially parallel to asurface of the substrate support 303 defined to support the substrate109. Also, each electron beam source 363 can be defined to generate andtransmit one or multiple electron beams 367. During operation, theelectron beam source 363 is operated to transmit the electron beam 367through the substrate processing region 302 as an ion generating gas,such as argon, is flowed through the substrate processing region 302. Inone embodiment, the ion generating gas is a component of a process gasmixture supplied from the process gas source 319, and flows into thesubstrate processing region 302 through the fluid transmission pathways316 in the top plate 315.

Electron beam 367 injection into the substrate processing region 302,such as that provided by the electron beam source 363, causes anincrease in charged particle production, i.e., ion production, withinthe substrate processing region 302 in the vicinity of the electron beam367. The electron beam 367 injection into the substrate processingregion 302 is optimized to create substantially more ions throughelectron impact ionization events as compared to radicals throughelectron impact dissociation of the process gas. In one embodiment, amethod to establish this preference for ionization relative todissociation may include one or more of optimization of a position ofthe electron beam 367 source, optimization of a number of electronsinjected into the processing region 302, and/or optimization of anenergy of the electron beam 367. Therefore, it should be appreciatedthat electron beam 367 injection into and through the substrateprocessing region 302 provides for spatial and temporal control of anincrease in ion density without substantially affecting radical density,thereby providing for an effective decoupling of ion density controlfrom radical density control within the substrate processing region 302.

The embodiment of FIG. 3A also includes a number of conductive grids 365positioned outside a perimeter of the substrate support 303 and abovethe substrate support 303. The conductive grids 365 are electricallyconnected to a power supply 387, so as to have a controlled voltagelevel applied to each of the conductive grids 365 in an independentlycontrolled manner. Depending on the particular embodiment, the powersupply 387 can be defined to transmit DC power, RF power, or acombination thereof, to the conductive grids 365.

In one embodiment, the conductive grids 365 are positioned at and overthe electron beam outlet of each electron beam source 363. In thisembodiment, the power to the conductive grid 365 can be controlled toenhance, or at least not inhibit, electron beam 367 transmission fromthe electron beam source 363 over which the conductive grid 365 ispositioned. And, a positive charge can be applied to a given conductivegrid 365 that is positioned on a far side of the substrate support 303away from an active electron beam source 363, such that the givenpositively charged conductive grid 365 functions as an electrical sinkfor the electron beam 367 transmitted by the active electron beam source363.

As previously mentioned, the system 300 can include one or more electronbeam sources 363. FIG. 3F shows a top view of the substrate support 303in a system 300 configuration in which an electron beam source 363 isdefined to transmit multiple spatially separated electron beams 367through the substrate processing region 302, above and across thesubstrate support 303, in a common direction, in accordance with oneembodiment of the present invention. The electron beam source 363 can bedefined and operated to transmit the electron beams 367 in either acontinuous or pulsed manner. Also, the electron beam source 363 can bedefined and operated to transmit the electron beams 367 in a spatiallysegmented manner, such that the electron beams 367 are transmitted inthe single common direction over a portion of the substrate support 303at a given time. In this case, the electron beam source 363 can bedefined and operated to transmit the spatially segmented electron beams367 in a temporally multiplexed manner, such that the electron beams 367are collectively transmitted across an entirety of the substrate support303 (and substrate 109 disposed thereon) in a time-averagedsubstantially uniform manner. In this manner, the electron beams 367collectively provide a substantially uniform ion generation effectacross the substrate support 303 and substrate 109 disposed thereon.

In the embodiment of FIG. 3F, a first conductive grid 365A is disposedover the electron beam outlet of the electron beam source 363. Thisfirst conductive grid 365A can be powered to facilitate/enhancetransmission of the electron beam 367 from the electron beam source 363.Also, in this embodiment, a second conductive grid 365B is disposed at aposition opposite the substrate support 303 from the electron beamsource 363. The second conductive grid 365B is electrically connected tothe power supply 387 so as to receive a positive electrical charge. Inthis manner, the second conductive grid 365B functions as an electricalsink for the electron beams 367 transmitted in the single commondirection across the substrate processing region 302 from the electronbeam source 363.

FIG. 3G shows a top view of the substrate support 303 in the system 300configuration in which multiple electron beam sources 363 are defined totransmit multiple spatially separated electron beams 367 through thesubstrate processing region 302, above and across the substrate support303, in respective multiple directions, in accordance with oneembodiment of the present invention. Each electron beam source 363 canbe defined and operated to transmit its electron beams 367 in either acontinuous or pulsed manner. Also, the electron beam sources 363 can bedefined and operated to transmit the electron beams 367 in a spatiallyrastered manner, such that the electron beams 367 are transmitted from aselect number of electron beam sources 363 at a given time. In thiscase, one or more of the electron beam sources 363 can be operated at agiven time. Also, in this embodiment, the electron beam sources 363 canbe defined and operated to transmit the spatially rastered electronbeams 367 in a temporally multiplexed manner, such that the electronbeams 367 are collectively transmitted across an entirety of thesubstrate support 303 (and substrate 109 disposed thereon) in atime-averaged substantially uniform manner. In one embodiment, each ofthe electron beam sources 363 is defined and operated to transmit itselectron beam 367 over a central location of the substrate support 303.

Additionally, in the embodiment of FIG. 3G, each of the conductive grids365 is electrically connected to the power supply 387, such that each ofthe conductive grids 365 can be electrically charged (either positive ornegative) in an independently controlled manner. In one embodiment, aconductive grid 365 that is disposed over the electron beam outlet of anactive electron beam source 363 is electrically charged to eitherenhance transmission of the electron beam 367 or not inhibittransmission of the electron beam 367. And, another conductive grid 365positioned opposite the substrate support 303 from the active electronbeam source 363 is supplied with a positive electrical charge, such thatthis conductive grid 365 functions as an electrical sink for theelectron beam 367 transmitted across the substrate processing region 302from the active electron beam source 363.

FIG. 3H shows a rasterized temporal sequence for operation of themultiple electron beam sources 363 of FIG. 3G, in accordance with oneembodiment of the present invention. As shown in FIG. 3H, the electronbeam sources 363 are defined to sequentially transmit the multiplespatially separated electron beams 367. For example, at a time (Time 1),a first electron beam source 363 is operated to transmit its electronbeams 367 across the substrate support 303. At a next time (Time 2) asecond electron beam source 363 adjacent to the first electron beamsource is operated to transmit its electron beams 367 across thesubstrate support 303. The remaining ones of the multiple electron beamsources 363 are operated in a sequential manner at successive times totransmit their electron beams 367 across the substrate support 303.Ultimately, a final electron beam source 363 is operated at a final time(Time 16) to transmit its electron beams 367 across the substratesupport 303. Then, the rasterized temporal sequence of electron beamsource 363 operation can be repeated, as necessary. It should beunderstood that in other embodiments, the electron beam sources 363 canbe activated in essentially any order, e.g., a non-sequential order, andfor essentially any time period so as to achieve a desired effect on theion density within the substrate processing region 302.

It should be understood that the number of electron beam sources 363shown in FIGS. 3G and 3H are provided by way of example. In oneembodiment, 36 separate electron beam sources 363 are deployed aroundthe periphery of the substrate support 303, and are spaced apart fromeach other such that adjacent ones of the 36 electron beam sources 363transmit their respective electron beams across the substrate support303 at an angular difference (θ) of about 10 degrees relative to thecenter of the substrate support 303. In other embodiments, a differentnumber of electron beam sources 363 can be deployed around the peripheryof the substrate support 303 in a substantially uniform spaced apartmanner. Regardless of the specific number of electron beam sourcesdeployed around the periphery of the substrate support 303, it should beunderstood that the electron beam sources 363 can be deployed andoperated to transmit their respective spatially rastered electron beams367 in a temporally multiplexed manner, such that the electron beams 367are collectively transmitted across an entirety of the substrate support303 (and substrate 109 disposed thereon) in a time-averagedsubstantially uniform manner. In this manner, the electron beams 367collectively provide a substantially uniform ion generation effectacross the substrate support 303 and substrate 109 disposed thereon.

In various embodiments, the electron beam sources 363 can be defined asdifferent types of electron beam sources. For example, in someembodiments, the electron beam source 363 are defined as one or more ofhollow cathode devices, electron cyclotron resonance devices,laser-driven devices, microwave-driven devices, inductively coupledplasma generation devices, and capacitively coupled plasma generationdevices. It should be understood that the above-mentioned types ofelectron beam sources 363 are provided by way of example. In otherembodiments, essentially any type of electron beam sources 363 can beutilized in the system 300, so long as the electron beam sources 363 aredefined to generate and transmit the required electron beams 367 throughthe substrate processing region 302, so as to achieve a desired effecton ion density within the substrate processing region 302 andcorresponding plasma processing result on the substrate 109.

FIG. 4A shows an example electron beam source 363 defined as a hollowcathode device 401, in accordance with one embodiment of the presentinvention. The hollow cathode device 401 is positioned outside aperimeter of the substrate support 303 and above the substrate support303. The hollow cathode device 401 has an outlet region 407 orientedtoward the substrate processing region 302 over the substrate support303. The hollow cathode device 401 can be disposed within the system 300so as to be electrically and RF isolated from surrounding chambermaterials. In one embodiment, the hollow cathode device 401 includes apair of electrodes 403A, 403B disposed on opposite sides of an interiorcavity of the hollow cathode device 401. One or both of the electrodes403A, 403B are electrically connected to receive power from the electronbeam power source 389. The electron beam power source 389 can be definedto include a DC power supply 389A, an RF power supply 389B, or acombination thereof. The RF power supply 389B is connected to theelectrodes 403A and/or 403B through matching circuitry 389C to provideimpedance matching to minimize reflection of the transmitted RF powerfrom the electrodes 403A and/or 403B.

In one embodiment, the electrodes 403A, 403B are positioned such thatone electrode 403A is disposed opposite the hollow cathode device 401interior from the electron beam 367 outlet of the hollow cathode device401, and the other electrode 403B is disposed next to the outlet of thehollow cathode device 401. However, it should be understood that inother embodiments, the electrodes 403A, 403B can be disposed in otherlocations and/or orientations within the interior cavity of the hollowcathode device 401. Additionally, in other embodiments, the hollowcathode device 401 can be defined to implement power delivery componentsother than electrodes 403A, 403B, so long as the power deliverycomponents are capable of conveying power to a process gas inside theinterior of the hollow cathode device 401, so as to transform theprocess gas into a plasma 405. For example, in one embodiment, the wallsof the hollow cathode device 401 are electrically conductive and servethe function of the power delivery components. In another exampleembodiment, the power delivery components are implemented as coilsdisposed proximate to the hollow cathode device 401.

The hollow cathode device 401 is also connected to the electron beam gassupply 388, such that the process gas for the electron beam generationcan be flowed in a controlled manner from the electron beam gas supply388 into the interior of the hollow cathode device 401. Upon enteringthe interior of the hollow cathode device 401, the process gas istransformed into the plasma 405 by the power emanating from theelectrodes 403A, 403B, or other type of power delivery component. In oneembodiment, RF power having a frequency of either 2 MHz, 27 MHz, 60 MHz,400 kHz, or combination thereof is transmitted to the electrodes 403A,403B, or other type of power delivery component, to transform theprocess gas into the plasma 405.

Additionally, in one embodiment, the hollow cathode device 401 isdefined to implement an energized electron beam 367 outlet region 407 toenhance electron extraction from the interior cavity of the hollowcathode device 401. In one embodiment, the energizable outlet region 407itself is defined as another hollow cathode. In one version of thisembodiment, the outlet region 407 is circumscribed by an electrode thatcan be powered by either DC power, RF power, or a combination thereof.As the reactive constituents from the plasma 405 flow through theenergizable outlet region 407, the power emanating from the electrodewill liberate fast electrons within the outlet region 407, which willenhance the electron beam 367 transmitted from the hollow cathode device401.

In one embodiment, the conductive grid 365 is disposed over the electronbeam 367 outlet region 407 of the hollow cathode device 401. Morespecifically, the conductive grid 365 is disposed between the outletregion 407 of the hollow cathode device 401 and the substrate processingregion 302 over the substrate support 303 to facilitate extraction ofelectrons from the plasma 405 within the interior cavity of the hollowcathode device 401. FIG. 4B shows a front view of the conductive grid365, in accordance with one embodiment of the present invention. In oneembodiment, the conductive grid 365 is electrically connected to receivepower from the conductive grid power supply 387. The power source 387can be defined to include a DC power supply 387A, an RF power supply387B, or a combination thereof. The RF power supply 387B is connected tothe conductive grid 365 through matching circuitry 387C to provideimpedance matching to minimize reflection of the transmitted RF powerfrom the conductive grid 365.

Additionally, in one embodiment, the conductive grid 365 is connected toa heater 409 to provide for independent temperature control of theconductive grid 365, which can be used to maintain a cleanliness stateof the conductive grid 365. In one embodiment, the conductive grid 365operates as an extraction grid to extract electron flux from the plasma405 within the interior cavity of the hollow cathode device 401.Additionally, in one embodiment, the conductive grid 365 can be operatedin a pulsed manner such that a polarity of the electrical charge on theconductive grid 365 is alternated between positive and negative betweenpulses. In this embodiment, the conductive grid 365 operates to extractelectron flux from the plasma 405 when supplied with a positive chargepulse, and extract ions from the plasma 405 when supplied with anegative charge pulse. Thus, in this embodiment, the conductive grid 365can be pulsed in an alternating manner between an ion extraction modeand an electron extraction mode. Also, this pulsing of the conductivegrid provides period averaged null current and access to ion drivenionization processes within the substrate processing region 302.Additionally, another conductive grid 365 disposed opposite thesubstrate support 303 from the outlet region 407 of the hollow cathodedevice 401 can be operated to have a positive charge to provide anelectrical sink for the electron beam 367 transmitted by the hollowcathode device 401.

FIG. 5A shows a variation of the plasma-driven substrate processingsystem 300 that implements a DC-biased surface electron beam source 503,in accordance with one embodiment of the present invention. The system300A of FIG. 5A includes the DC-biased electron beam source 503 in lieuof the electron beam sources 363 and conductive grids 365. For ease ofdescription, the DC-biased electron beam source 503 is referred tohereafter as an electrode 503. The electrode 503 is disposed within anelectrically insulating member 501, such that a surface of the electrode503 is exposed to the substrate processing region 302. Also, theelectrode 503 is disposed within the processing chamber 301 separatefrom the substrate support 303. In one embodiment, the electrode 503 isdefined as a conductive band disposed outside a perimeter of thesubstrate support 303 and above the substrate support 303 within thesubstrate processing region 302 of the processing chamber 301. In oneembodiment, the electrode 503 is defined as a band or strap thatcircumscribes the substrate processing region 302 around the substratesupport 303.

In the system 300A, the electrode 503 is electrically connected to apower supply 505. In one embodiment, the power supply 505 is defined toapply electrical power to the electrode 503 so as to attract ions withinthe substrate processing region 302 toward the electrode 503 andliberate electrons from the electrode 503 into the substrate processingregion 302. In different embodiments, the electrical power supplied tothe electrode 503 from the power supply 505 can be DC power, RF power,or a combination of DC and RF power. In one embodiment, a negativevoltage is applied to the electrode 503 by the power supply 505.However, in other embodiments, the voltage applied to the electrode 503by the power supply 505 can be either negative or positive. For example,in one embodiment, the power supply 505 is defined to supply a positivevoltage to the electrode 503, thereby attracting electrons and repellingpositively charged ions. Also, in one embodiment, the power supply 505is defined to apply power to the electrode 503 in a pulsed manner and/orin an alternating polarity manner.

FIG. 5B shows a close-up view of the electrode 503, in accordance withone embodiment of the present invention. In one embodiment, theelectrode 503 provides a DC-biased surface from which an incident ionflux (J_(ion)) generates an electron flux (J_(e-)), i.e., electron beam,that leaves the surface of the electrode 503 in a direction toward thesubstrate processing region 302. In one embodiment, the ions in the ionflux (J_(ion)) that are incident upon the electrode 503 are non-inertand are passivating, such as Si ions. In this embodiment, the DC-biasedsurface of the electrode 503 can be utilized to compensate for thepassivating species that are produced through radical interactions. Inone embodiment, the electrode 503 can be powered with either DC power,RF power, or a combination thereof. Also, in one embodiment, a lowfrequency RF power is supplied to the electrode 503.

Additionally, in one embodiment, the electrode 503 is sized to create ahollow cathode effect within the substrate processing region 302. Morespecifically, if the DC-biased surface of the electrode 503 is definedas a large enough band or strap that circumscribes the substrateprocessing region 302, such that electrons emitted from the electrode503 reach the opposing portion of the electrode 503 with sufficientenergy, a hollow cathode configuration may be formed within thesubstrate processing region 302 itself, thereby further enhancing theionization within the substrate processing region 302.

FIG. 6A shows a variation of the plasma-driven substrate processingsystem 300 that implements a planar DC-biased surface electron beamsource 601, in accordance with one embodiment of the present invention.Relative to the system 300 of FIG. 3A, the system 300B of FIG. 6Aincludes the planar DC-biased electron beam source 601 in lieu of theelectron beam sources 363 and conductive grids 365. For ease ofdescription, the DC-biased electron beam source 601 is referred tohereafter as a planar electrode 601. In one embodiment, the planarelectrode 601 is defined as a planar conductive segment 601 disposedabove the substrate support 303 within the substrate processing region302. In one embodiment, the planar electrode 601 is implemented withinthe system 300B in combination with the electrode 503 as discussed abovewith regard to FIGS. 5A-5B.

For example, in one embodiment, the planar electrode 601 is defined on abottom surface of the top plate 315 in an orientation facing thesubstrate support 303, so as to face the substrate processing region302. In one embodiment, the planar electrode 601 is electricallyinsulated from the top plate 315 by an insulating member 603. Also, inthis embodiment, it should be understood that each of the planarelectrode 601 and the insulating member 603 includes a number ofthrough-holes formed in alignment with the number of fluid transmissionpathways 316 present in the top plate 315, such that both planarelectrode 601 and insulating member 603 avoid interfering with a flow ofreactive constituents from the plasma generation chamber 355 into thesubstrate processing region 302.

In the system 300B, the planar electrode 601 is electrically connectedto a power supply 605. In one embodiment, the power supply 605 isdefined to apply a negative voltage to the planar electrode 601 so as toattract ions within the substrate processing region 302 toward theplanar electrode 601 and liberate electrons from the planar electrode601 into the substrate processing region 302. In one embodiment, thepower supply 605 is defined to apply power to the planar electrode 601in a pulsed manner. Also, in one embodiment, the power supply 605 isdefined to supply a positive voltage to the planar electrode 601,thereby attracting electrons and repelling positively charged ions.

FIG. 6B shows a close-up view of the planar electrode 601, in accordancewith one embodiment of the present invention. In one embodiment, theplanar electrode 601 provides a DC-biased surface from which an incidention flux (J_(ion)) generates an electron flux (J_(e-)), i.e., electronbeam, that leaves the surface of the planar electrode 601 in a directiontoward the substrate processing region 302. In one embodiment, the ionsin the ion flux (J_(ion)) that are incident upon the planar electrode601 are non-inert and are passivating, such as Si ions. In thisembodiment, the DC-biased surface of the planar electrode 601 can beutilized to compensate for the passivating species that are producedthrough radical interactions. In one embodiment, the planar electrode601 can be powered with either DC power, RF power, or a combinationthereof. Also, in one embodiment, a low frequency RF power is suppliedto the electrode 601.

As previously discussed, a total flow area of the fluid transmissionpathways 316 between the plasma generation chamber 355 and the substrateprocessing region 302 can be quite small. For example, the fluidtransmission pathways 316 can include small tube diameters or a smallnumbers of holes of small diameter in order to maintain an adequatepressure differential between the higher pressure plasma generationchamber 355 and the lower pressure substrate processing region 302.Therefore, because large gas densities, i.e., high gas pressures, may beneeded in the plasma generation chamber 355 to achieve a sufficientamount of electron production, it may not be feasible to simply increasethe flow area of the fluid transmission pathways 316 to obtain a higherion flux from the plasma generation chamber 355 into the substrateprocessing region 302.

To overcome the geometric limits to ion transfer efficiency associatedwith the fluid transmission pathways 316, one embodiment of the presentinvention utilizes the fluid transmission pathways 316 as supplementaryion generation regions, i.e., as plasma boosters. FIG. 7 shows avariation of the plasma-driven substrate processing system 300 thatutilizes the fluid transmission pathways 316 as supplementary iongeneration regions, in accordance with one embodiment of the presentinvention. In the embodiment of FIG. 7, the top plate 315 in the system300 of FIG. 3A is replaced by an energizable top plate 701. As with thetop plate 315, the energizable top plate 701 includes the number offluid transmission pathways 316 formed through the energizable top plate701 so as to extend from the plasma generation chamber 355 to thesubstrate processing region 302. However, the energizable top plate 701includes a number of power delivery components 702 disposed proximate toeach of the number of fluid transmission pathways 316. The powerdelivery components 702 are defined to deliver power to the fluidtransmission pathways 316 so as to generate supplemental plasma 704within the fluid transmission pathways 316. The fluid transmissionpathways 316 are defined to supply reactive constituents of both theplasma 359 and the supplemental plasma 704 to the substrate processingregion 302.

The system 300C also includes a power source 703 defined to supply DCpower, RF power, or a combination thereof, to the power deliverycomponents 702. The power delivery components 702 in turn function totransmit power through the fluid transmission pathways 316 so as totransform process gas within the fluid transmission pathways 316 intothe supplemental plasma 704. In one embodiment, the system 300C can alsoinclude a process gas source 709 in fluid communication with each of thefluid transmission pathways 316 to provide for supply of a secondaryprocess gas to each of the fluid transmission pathways 316. The powertransmitted from the power delivery components 702 can be used totransform the secondary process gas into the supplemental plasma 704.However, in another embodiment, the system 300C may not utilize thesecondary process gas source 709. In this embodiment, the power deliverycomponents 702 are defined to transform process gas that flows throughthe fluid transmission pathways 316 from the plasma generation chamber355 into the supplemental plasma 704. In this embodiment, the fluidtransmission pathways 316 are operated as plasma amplifying region.

It should be understood that in the system 300C the fluid transmissionpathways 316, power delivery components 702, and power source 703 can bedefined in many ways to form different types of supplemental plasma 704generation regions within the fluid transmission pathways 316. Forexample, in various embodiments, the fluid transmission pathways 316,power delivery components 702, and power source 703 can be defined suchthat the fluid transmission pathways 316 operate as flow-through hollowcathodes, flow-through capacitively coupled regions, flow-throughinductively coupled regions, flow-through magnetron driven regions,flow-through laser driven regions, or a combination thereof. In otherwords, in various embodiments, each fluid transmission pathway 316 canbe operated as either a hollow cathode, a capacitively coupled source,an inductive source (with inductive coils wrapping the fluidtransmission pathway), through a magnetron effect, or through anotherkind of ionizing means, such as through irradiation of points in thefluid transmission pathway with focused laser light. In one embodiment,the fluid transmission pathways 316 are operated as a hollow cathodemedium or with direct electron beam injection into the fluidtransmission pathways 316 in order to achieve a sufficient amount ofhigh energy electrons to produce significant amounts of ionization.

It should be understood that generation of the supplemental plasma 704within the fluid transmission pathways 316 provides for an unimpededline-of-sight transmission of ions from the supplemental plasma 704 intothe substrate processing region 302, thereby providing for a controlledincrease in ion flux entering the substrate processing region 302.Additionally, in one embodiment, the power delivery components 702include electron beam sources defined to generate electron beams andtransmit these electron beams through the fluid transmission pathways316, so as to enhance ion generation within the supplemental plasma 704formed within the fluid transmission pathways 316.

Additionally, in one embodiment, the system 300C can optionally includean electrode 711 disposed in the plasma generation chamber 355 to drivecharged species from the plasma generation chamber 355 through the fluidtransmission pathways 316 into the substrate processing region 302.Also, the electrode 711 can function to drive charged species from thesupplemental plasma 704 within the fluid transmission pathways 316 intothe substrate processing region 302. It should be understood that theelectrode 711 can be connected to a power source to be supplied with DCpower, RF power, or a combination thereof. Also, the polarity of thecharge on the electrode 711 can be controlled and varied in a prescribedmanner. For example, in one embodiment, power can be supplied to theelectrode 711 in a pulsed manner.

Additionally, in one embodiment, the system 300C can optionally includethe electrode 503 and corresponding power source 505, as previouslydiscussed with regard to FIGS. 5A and 5B. Also, in one embodiment, thesystem 300C can optionally include the electrode beam sources 363,conductive grids 365, power sources 387 and 389, and electron beam gassupply 388, as previously discussed with regard to FIGS. 3A through 4B.And, in one embodiment, the system 300C can optionally include theplanar electrode 601 and insulating member 603, as previously discussedwith regard to FIGS. 6A and 6B. In this embodiment, the planar electrode601 can be operated as an extraction grid disposed within the substrateprocessing region 302 to attract charged species from the fluidtransmission pathways 316 into the substrate processing region 302.Depending on the polarity of the electric charge supplied to the planarelectrode 601, the charged species attracted from the fluid transmissionpathways 316 into the substrate processing region 302 can include eitherelectrons or positively charged ions. As with the electrode 711, itshould be understood that each of the electrode 503 and planar electrode601 can be supplied with DC power, RF power, or a combination thereof.Also, as with the electrode 711, each of the electrode 503 and planarelectrode 601 can be operated in an independently controlled manner,e.g., in a continuously powered manner or pulsed manner.

In one embodiment, the remote plasma 359 source within the plasmageneration chamber 355 can be used as an electron beam source to affection-to-radical flux control in the substrate processing region 302. Ifthe remote plasma 359 source within the plasma generation chamber 355 isoperated with a substantially negative potential relative to thesubstrate processing region 302, then electrons can be accelerated fromthe negative potential of the plasma generation chamber 355 through thefluid transmission pathways 316 to the positive potential of thesubstrate processing region 302. As the energetic electrons travelthrough the fluid transmission pathways 316 and into the substrateprocessing region 302, the energetic electrons cause ionization in anenergy regime in which simple dissociation processes are not favored.Also, if the energetic electrons scatter as they travel through thefluid transmission pathways 316, the energetic electrons can generateadditional secondary electrons, especially given that the secondaryelectron generation coefficient can be very high and often higher thanthe ion generation coefficient associated with electron interactionprocesses.

It should be understood that different kinds of remote plasma 359sources can be used for electron beam extraction from the plasmageneration chamber 355 into the substrate processing region 302. Forexample, some embodiments can operate the plasma generation region 355as a capacitively coupled plasma 359 source generation region, aninductively coupled plasma 359 source generation region, or a microwaveplasma 359 source generation region in combination with DC biasing.Also, if the electrical potential difference between the plasmageneration chamber 355 and substrate processing region 302 is inadequatefor electron beam extraction from the plasma generation chamber 355 intothe substrate processing region 302, an electron extraction grid can beused to extract electrons from the plasma generation chamber 355 into asecondary plasma source region, e.g., within the fluid transmissionpathways 316, where the extracted electrons can produce more ions.

In view of the foregoing, it should be appreciated that spatial and/ortemporal multiplexing of electron beam injection into the substrateprocessing region 302 facilitates modulation of the ion flux to radicalflux within the substrate processing region 302. Also, it should beappreciated that use of electron beam excited plasma source incombination with a primarily radical constituent plasma source canprovide a dynamic range of ion flux-to-radical flux ratio control thatis not achievable by any other means.

FIG. 8 shows a flowchart of a method 800 for processing a semiconductorsubstrate, in accordance with one embodiment of the present invention.In one embodiment, the plasma-driven substrate processing system 300 ofFIGS. 3A through 4B can be used to perform the method of FIG. 8. Themethod 800 includes an operation 801 for placing a substrate on asubstrate support in exposure to a processing region. The method 800also includes an operation 803 for generating a plasma in a plasmageneration region separate from the processing region. The method 800also includes an operation 805 for supplying reactive constituents ofthe plasma from the plasma generation region to the processing region.The method 800 further includes an operation 807 for injecting electronsinto the processing region over the substrate, whereby the injectedelectrons modify an ion density in the processing region to affectprocessing of the substrate.

In one embodiment of the method 800, injecting electrons into theprocessing region includes transmitting an electron beam along atrajectory substantially parallel to a top surface of the substrate. Inone instance of this embodiment, the trajectory of the electron beamextends in a linear manner from a first location outside a periphery ofthe substrate support and above the substrate support to a secondlocation outside the periphery of the substrate support and above thesubstrate support. In another instance of this embodiment, the method800 can include generating an electric steering field within theprocessing region, such that the trajectory of the electron beam extendsthrough the processing region in a non-linear manner as controlled bythe electric steering field. Also, in one embodiment, the method 800includes an operation for applying a positive electrical charge to aconductive grid at the second location, i.e., at the electron beamterminating location, such that the conductive grid functions as anelectrical sink for the electron beam transmitted along the trajectory.In various embodiments of the method 800, the electrons can be injectedinto the processing region in a pulsed manner, or in a continuousmanner.

In one embodiment, the operation 807 for injecting electrons into theprocessing region includes transmitting multiple spatially separatedelectron beams through the processing chamber above and across a topsurface of the substrate. In one instance of this embodiment, each ofthe multiple spatially separated electron beams is transmitted in acommon direction, such that the multiple spatially separated electronbeams are transmitted in a substantially parallel manner above andacross the top surface of the substrate. In another instance of thisembodiment, the multiple spatially separated electron beams aretransmitted in different multiple directions above and across the topsurface of the substrate and substantially parallel to the top surfaceof the substrate. Also, in one embodiment, different ones of themultiple spatially separated electron beams are transmitted at differenttimes such that electrons are injected in a time-averaged substantiallyuniform manner throughout the processing region in exposure to thesubstrate. The method 800 can also include an operation for applying abias voltage across the processing region from the substrate support soas to attract ions that are generated as a result of the injectedelectrons toward the substrate.

FIG. 9 shows a flowchart of a method 900 for processing a semiconductorsubstrate, in accordance with one embodiment of the present invention.In one embodiment, the plasma-driven substrate processing systems 300A,300B of FIGS. 5A through 6B, or combination thereof, can be used toperform the method of FIG. 9. The method 900 includes an operation 901for placing a substrate on a substrate support in exposure to aprocessing region. The method 900 also includes an operation 903 forgenerating a plasma in a plasma generation region separate from theprocessing region. The method 900 also includes an operation 905 forsupplying reactive constituents of the plasma from the plasma generationregion to the processing region. The method 900 further includes anoperation 907 for supplying power to one or more electrodes disposedwithin the processing region separate from the substrate support,whereby the power supplied to the one or more electrodes injectselectrons from the one or more electrodes into the processing region soas to modify an ion density in the processing region to affectprocessing of the substrate.

In one embodiment, the one or more electrodes includes a conductive banddisposed outside a perimeter of the substrate support and above thesubstrate support in exposure to the processing region, such as theelectrode 503 of FIG. 5A. In one embodiment, the conductive band isformed as a continuous structure that circumscribes the perimeter of thesubstrate support. Also, in one embodiment, the one or more electrodesincludes a planar conductive segment disposed above and over thesubstrate support in exposure to the processing region, such as theplanar electrode 601 of FIG. 6A. Also, in one embodiment, the one ormore electrodes includes both a conductive band disposed outside aperimeter of the substrate support and above the substrate support inexposure to the processing region, and a planar conductive segmentdisposed above and over the substrate support in exposure to theprocessing region.

In one embodiment, supplying power to one or more electrodes in theoperation 907 includes supplying direct current power, radiofrequencypower, or a combination of direct current power and radiofrequency powerto the one or more electrodes. Also, in one embodiment, the power issupplied to one or more electrodes in a pulsed manner. In anotherembodiment, the power is supplied to one or more electrodes in acontinuous manner. Also, in one embodiment, supplying power to one ormore electrodes in the operation 907 includes alternating a polarity ofelectric charge on the one or more electrodes. Additionally, in oneembodiment, the method can include an operation for applying a biasvoltage across the processing region from the substrate support so as toattract ions that are generated as a result of the injected electronstoward the substrate.

FIG. 10 shows a flowchart of a method 1000 for processing asemiconductor substrate, in accordance with one embodiment of thepresent invention. In one embodiment, the plasma-driven substrateprocessing system 300C can be used to perforin the method of FIG. 10. Inone embodiment, the plasma-driven substrate processing system 300C canbe combined with components of one or more of the plasma-drivensubstrate processing systems 300, 300A, and 300B to perform the methodof FIG. 10. The method 1000 includes an operation 1001 for placing asubstrate on a substrate support in exposure to a processing region. Themethod 1000 also includes an operation 1003 for generating a plasma in aplasma generation region separate from the processing region. The method1000 also includes an operation 1005 for supplying reactive constituentsof the plasma from the plasma generation region through a plurality offluid transmission pathways into the processing region, whereby thereactive constituents of the plasma affect processing of the substrate.The method 1000 further includes an operation 1007 for generating asupplemental plasma in the plurality of fluid transmission pathways. Themethod 1000 further includes an operation 1009 for supplying reactiveconstituents of the supplemental plasma from the plurality of fluidtransmission pathways into the processing region, whereby the reactiveconstituents of the supplemental plasma affect processing of thesubstrate.

In one embodiment, generating the supplemental plasma in operation 1007includes operating the plurality of fluid transmission pathways aseither flow-through hollow cathodes, flow-through capacitively coupledregions, flow-through inductively coupled regions, flow-throughmagnetron driven regions, flow-through laser driven regions, or acombination thereof. Also, in one embodiment, generating thesupplemental plasma in the plurality of fluid transmission pathways inoperation 1007 includes transmitting direct current power,radiofrequency current power, or a combination of direct current powerand radiofrequency power through the plurality of fluid transmissionpathways. In one embodiment, the power is transmitted through theplurality of fluid transmission pathways in a pulsed manner. In anotherembodiment, the power is transmitted through the plurality of fluidtransmission pathways in a continuous manner. Additionally, in oneembodiment, generating the supplemental plasma in the plurality of fluidtransmission pathways in operation 1007 includes supplying a process gasto the interior of each of the plurality of fluid transmission pathways.

In one embodiment, supplying reactive constituents of the plasma fromthe plasma generation region through the plurality of fluid transmissionpathways into the processing region in operation 1005 includes operatingan electrode disposed in the plasma generation region to drive chargedspecies from the plasma generation region through the plurality of fluidtransmission pathways into the processing region. Also, in oneembodiment, supplying reactive constituents of the supplemental plasmafrom the plurality of fluid transmission pathways into the processingregion in operation 1009 includes operating an extraction grid disposedwithin the processing chamber to attract charged species from theplurality of fluid transmission pathways into the processing region.

In one embodiment, the method 1000 can further include an operation forinjecting electrons into the processing region over the substrate,whereby the injected electrons modify an ion density in the processingregion to affect processing of the substrate. Also, in one embodiment,the method 1000 can include an operation for supplying power to one ormore electrodes disposed within the processing region separate from thesubstrate support, whereby the power supplied to the one or moreelectrodes injects electrons from the one or more electrodes into theprocessing region so as to modify an ion density in the processingregion to affect processing of the substrate.

While this invention has been described in terms of several embodiments,it will be appreciated that those skilled in the art upon reading thepreceding specification and studying the drawings will realize variousalterations, additions, permutations and equivalents thereof. Thepresent invention includes all such alterations, additions,permutations, and equivalents as fall within the true spirit and scopeof the invention.

1. A semiconductor substrate processing system, comprising: a processingchamber; a substrate support defined to support a substrate in theprocessing chamber; a plasma chamber defined separate from theprocessing chamber, the plasma chamber defined to generate a plasma; aplurality of fluid transmission pathways fluidly connecting the plasmachamber to the processing chamber, the plurality of fluid transmissionpathways defined to supply reactive constituents of the plasma from theplasma chamber to the processing chamber; and an electron beam sourcedefined to generate an electron beam and transmit the electron beamthrough the processing chamber above and across the substrate support.2. A semiconductor substrate processing system as recited in claim 1,wherein the electron beam source is defined to transmit the electronbeam along a trajectory substantially parallel to a surface of thesubstrate support defined to support the substrate.
 3. A semiconductorsubstrate processing system as recited in claim 1, wherein the electronbeam source is defined to transmit multiple spatially separated electronbeams through the processing chamber above and across the substratesupport in a common direction.
 4. A semiconductor substrate processingsystem as recited in claim 1, wherein the electron beam source isdefined to transmit multiple spatially separated electron beams throughthe processing chamber above and across the substrate support inrespective multiple directions.
 5. A semiconductor substrate processingsystem as recited in claim 4, wherein the electron beam source isdefined to sequentially transmit the multiple spatially separatedelectron beams.
 6. A semiconductor substrate processing system asrecited in claim 1, further comprising: a plurality of conductive gridspositioned outside a perimeter of the substrate support and above thesubstrate support, the plurality of conductive grids electricallyconnected to a power supply so as to have a controlled voltage levelapplied to each of the plurality of conductive grids in a independentlycontrolled manner.
 7. A semiconductor substrate processing system asrecited in claim 6, wherein the electron beam source is defined as ahollow cathode positioned outside a perimeter of the substrate supportand above the substrate support, the hollow cathode having an outletoriented toward a region of the processing chamber over the substratesupport, and wherein a given one of the plurality of conductive grids isdisposed between the outlet of the hollow cathode and the region of theprocessing chamber over the substrate support to facilitate extractionof electrons from the hollow cathode.
 8. A semiconductor substrateprocessing system as recited in claim 7, wherein another one of theplurality of conductive grids is disposed opposite the substrate supportfrom the outlet of the hollow cathode to provide an electrical sink forthe electron beam to be transmitted by the hollow cathode.
 9. Asemiconductor substrate processing system as recited in claim 7, furthercomprising: a heater connected to the plurality of conductive grids tocontrol a temperature of the plurality of conductive grids.
 10. Asemiconductor substrate processing system as recited in claim 7, furthercomprising: a gas supply in fluid communication with an interior regionof the hollow cathode, the gas supply defined to supply a process gas tothe interior region of the hollow cathode; and a power supply inelectrical communication with one or more power delivery componentswithin the interior region of the hollow cathode, the power supplydefined to supply direct current power, radiofrequency power, or acombination of direct current power and radiofrequency power to the oneor more power delivery components within the interior region of thehollow cathode to provide for transformation of the process gas into aplasma within the interior region of the hollow cathode.
 11. A methodfor processing a semiconductor substrate, comprising: placing asubstrate on a substrate support in exposure to a processing region;generating a plasma in a plasma generation region separate from theprocessing region; supplying reactive constituents of the plasma fromthe plasma generation region to the processing region; and injectingelectrons into the processing region over the substrate, whereby theinjected electrons modify an ion density in the processing region toaffect processing of the substrate.
 12. A method for processing asemiconductor substrate as recited in claim 11, wherein injectingelectrons into the processing region includes transmitting an electronbeam along a trajectory substantially parallel to a top surface of thesubstrate.
 13. A method for processing a semiconductor substrate asrecited in claim 12, wherein the trajectory of the electron beam extendsin a linear manner from a first location outside a periphery of thesubstrate support and above the substrate support to a second locationoutside the periphery of the substrate support and above the substratesupport.
 14. A method for processing a semiconductor substrate asrecited in claim 13, further comprising: applying a positive electricalcharge to a conductive grid at the second location such that theconductive grid functions as an electrical sink for the electron beamtransmitted along the trajectory.
 15. A method for processing asemiconductor substrate as recited in claim 11, wherein the electronsare injected into the processing region in a pulsed manner.
 16. A methodfor processing a semiconductor substrate as recited in claim 11, whereininjecting electrons into the processing region includes transmittingmultiple spatially separated electron beams through the processingchamber above and across a top surface of the substrate.
 17. A methodfor processing a semiconductor substrate as recited in claim 16, whereineach of the multiple spatially separated electron beams is transmittedin a common direction such that the multiple spatially separatedelectron beams are transmitted in a substantially parallel manner aboveand across the top surface of the substrate.
 18. A method for processinga semiconductor substrate as recited in claim 16, wherein different onesof the multiple spatially separated electron beams are transmitted atdifferent times such that electrons are injected in a time-averagedsubstantially uniform manner throughout the processing region inexposure to the substrate.
 19. A method for processing a semiconductorsubstrate as recited in claim 16, wherein the multiple spatiallyseparated electron beams are transmitted in different multipledirections above and across the top surface of the substrate andsubstantially parallel to the top surface of the substrate.
 20. A methodfor processing a semiconductor substrate as recited in claim 11, whereindifferent ones of the multiple spatially separated electron beams aretransmitted at different times such that electrons are injected in atime-averaged substantially uniform manner throughout the processingregion in exposure to the substrate.